Water soluble sheet material

ABSTRACT

An improved circumscribing plug wrap and tipping material are provided. The plug wrap and tipping material are a cast sheet which includes 20 to 70 percent by weight water dispersible cellulose material, 20 to 70 percent by weight of a water soluble film forming material and 0 to 10 percent by weight of a humectant. A smoking article (e.g., cigarette) using such plug wrap or tipping material or both is also provided.

FIELD AND BACKGROUND OF THE INVENTION

[0001] The present invention relates to plug wrap or tipping material, and particularly plug wrap or tipping material that is water dispersible.

[0002] Increased environmental concerns have led to the desire of cigarette manufacturers to produce cigarettes, and particularly cigarette filters which degrade over time. People often inadvertently discard their cigarettes, and more particularly the filters thereof, into the environment. A proposed solution is provided in U.S. Pat. No. 5,453,144 to Kauffman et al., which relates to a water sensitive hot melt adhesive. Such an adhesive is used for the plug wrap bond, and loses strength when flushed or discarded into the environment, thus reducing the amount of paper in the environment.

[0003] There, however, remains a need for a paper for plug wrap or tipping material or both that is environmentally friendly. Such a paper should be sufficiently strong to be used for its intended purpose, but will readily disperse once inadvertently placed into the environment.

SUMMARY OF THE INVENTION

[0004] To this end, the present invention provides a plug wrap or tipping material that having sufficient strength so as to be able to be used on conventional cigarette making apparatus, yet is water dispersible when in advertently discarded into the environment. The improved plug wrap of the present invention comprises an improved circumscribing plug wrap for a filter element of a smoking article, the plug wrap comprising a cast sheet of 20 to 70 percent by weight water dispersible cellulose material, 20 to 70 percent by weight of a water soluble film forming material and 0 to 10 percent by weight of a humectant.

[0005] The present invention also provides an improved cigarette tipping paper comprising a cast sheet of 20 to 70 percent by weight water dispersible cellulose material, 20 to 70 percent by weight of a water soluble film forming material and 0 to 10 percent by weight of a humectant, wherein the cast sheet is printed with an ink pattern.

[0006] The present invention also provides a cigarette having a charge of smokable material including tobacco cut filler wrapped in a circumscribing wrapping material to form a smokable rod and filter plug positioned adjacent to one end of the smokable rod, the filter plug comprising a filter element and a circumscribing filter plug wrap comprising a cast sheet comprising a cast sheet of 20 to 70 percent by weight water dispersible cellulose material, 20 to 70 percent by weight of a water soluble film forming material and 0 to 10 percent by weight of a humectant.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]FIG. 1 is a diagrammatic cross sectional illustration of a cigarette showing the rod of smokable material and a filter element.

[0008]FIG. 2 is a diagrammatic cross sectional illustration of a cigarette showing the rod of smokable material, the filter element, and a second filter element.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The plug wrap and tipping material of this invention, and cigarettes containing the plug wrap or tipping material or both of this invention will be described with reference to FIGS. 1 and 2 in which like elements are given like reference throughout.

[0010] An embodiment of this invention shown in FIG. 1 is a smoking article 2 in the form of a cigarette. The cigarette comprises a generally cylindrical rod 4 of smokable material 6 contained in a wrapping material 8. Examples of suitable types of tobacco materials include flue-cured, Burley, Maryland or Oriental tobaccos, and blends thereof. The tobacco material can be provided in the form of tobacco lamina; processed tobacco materials such as volume expanded or puffed tobacco, processed tobacco stems such as cut-rolled or cut puffed stems, reconstituted tobacco materials; or blends thereof. Certain reconstituted tobacco materials are described in U.S. Pat. No. 4,962,774 to Thomasson et al.; U.S. Pat. No. 4,987,906 to Young et al.; U.S. Pat. No. 5,159,942 to Brinkley et al.; U.S. Pat. No. 5,099,864 to Young et al.; U.S. Pat. No. 5,143,097 to Sohn et al.; and U.S. Pat. No. 5,056,537 to Brown et al.; and in European Patent Application Nos. 419,733 to Fagg the disclosures of which are incorporated herein in their entirety. Certain blends are described in U.S. Pat. No. 4,924,888 to Perfetti et al.; U.S. Pat. No. 4,942,888 to Montoya et al.; and U.S. Pat. No. 4,998,541 to Perfetti et al. the disclosures of which are incorporated herein in their entirety. The smokable material generally is provided as conventionally employed in the manufacture of cigarettes (i.e., as strands of material provided at about 32 cuts per inch and treated with conventional additives such as flavorants).

[0011] Typically, this wrapping material 8 is a conventional cigarette wrapping paper although the plug wrap material of the present invention could be used. The ends of the rod are open to expose the smoking material. Rod 4 has a diameter comparable to that of conventional cigarettes and generally ranges from about 7 mm to about 8 mm. Rod 4 has a longitudinally extending length comparable to the tobacco rod length of conventional cigarettes and generally ranges from about 55 mm to about 85 mm. The smoking article further comprises filter plug 10 positioned adjacent to one end of rod 4 such that the filter plug is axially aligned with the rod in an end-to-end relation. Filter plug 10 has a substantially cylindrical shape, and the diameter of the rod is substantially equal to the diameter of the filter plug. Preferably, the filter plug substantially abuts the rod. The ends of the filter plug are open to permit the passage of air and smoke.

[0012] The filter plug comprises a filter element 12 which is overwrapped (i.e., enveloped) along the longitudinally extending surface thereof with an improved circumscribing plug wrap material 14 of the invention. The improved circumscribing plug wrap material of the present invention includes a cast sheet of 20 to 70 percent by weight water dispersible cellulose material, 20 to 70 percent by weight of a water soluble film forming material and 0 to 10 percent by weight of a humectant. Suitable water dispersible cellulose materials include wood pulp (hardwood and softwood, bleached or unbleached), flax fibers, esparto fiber, sisel fibers, or any other cellulose materials that when exposed to water become unbound to each other but do not appreciable dissolve or become soluble. Preferably the water dispersible cellulose material has a Canadian Standard freeness of −30 to −650 CSF units. CSF measures how easily or freely water will drain from a paper sheet during production. A negative value indicates that the cellulose material has been refined beyond its inversion point, and a more negative value indicates a more refined material.

[0013] The water soluble film forming material should be capable of binding the water dispersible cellulose material together during casting but readily dissolves in water when exposed thereto thereby releasing the cellulose material to be dispersed within water. Preferably, the film forming material is a water soluble cellulose material or a water soluble polysaccharide gum. Suitable water soluble cellulose material includes carboxylmethyl cellulose and salts and derivatives thereof; methyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, ethyl hydroxyethyl cellulose, hydroxylethyl cellulose and blends thereof. Suitable polysaccharide gums include guar gum, xanthan gum, locust bean gum, gum arabic, sodium alginate, carrageenan gum and tamarind gum and blends thereof. The film forming material may be a combination (e.g., blend or mixture) of the water soluble cellulose material and the water soluble polysaccharide gum.

[0014] Suitable humectants include polyhydric alcohols, aliphatic esters of mono-, di- or polycarboxylic acid and combinations thereof. A particularly preferred humectant is glycerin.

[0015] Filter plug 10 is attached to rod 4 by the tipping material 16 of the present invention which circumscribes both the filter plug and an adjacent region of the rod. The inner surface of the tipping material is fixedly secured to the outer surface of the filter plug and to the wrapping material of an adjacent region of the rod. The tipping material circumscribes the rod over a longitudinal length which can vary but is typically that length sufficient to provide good attachment of the filter plug to the rod. The tipping material includes a cast sheet of 20 to 70 percent by weight water dispersible cellulose material, 20 to 70 percent by weight of a water soluble film forming material and 0 to 10 percent by weight of a humectant. Various fillers can be included to provide weight or color. A particularly preferred filler is calcium carbonate. Preferably about 30 to 50 percent by weight of filler is added. The tipping material or plug wrap material may be tinted or colored using a coloring agent such as finely ground tobacco or can be printed to give the appearance of conventional papers.

[0016] The manner in which filter elements of the present invention are manufactured can vary. Filter tow (e.g., cellulose acetate or polypropylene tow) can be processed using a tow processing unit (e.g., an E-60 unit available from Arjay Equipment Corp., Inc.) and formed into a filter rod using a rod making unit (e.g., a KDF-2 rod making apparatus from Hauni-Werke Korber & Co., K.G.). Additionally, a conventional non-water soluble lip release agent (e.g., ethyl cellulose) may be coated onto tipping material.

[0017] An embodiment of this invention shown in FIG. 2 is a smoking article 2 in the form of a cigarette comprising a generally cylindrical rod 4 of smokable material 6 contained in wrapping material 8. The smoking article further comprises a filter region including filter element 12 which is overwrapped with the circumscribing wrap material 14 of the invention. The overwrapped filter element is axially aligned with the rod in an end-to-end relation, has a substantially cylindrical shape, has a diameter which is slightly less than that of the rod, and preferably substantially abuts to the rod. The filter region further includes a second filter element 18 which is axially aligned with the filter element. Optionally, the second filter element is overwapped with a circumscribing wrap material 14 a of the invention or with a conventional filter plug wrap, or the like. Second filter element 18 is axially aligned with filter element 12 in an end-to-end relation, has a substantially cylindrical shape, has a diameter in combination with a combining wrap material 17 of the invention which is substantial equal to that of the rod, and preferably substantially abuts the filter element. Second filter element 18 can be conventional tow material such as cellulose acetate, polypropylene, or the like. Second filter element 18 can have a generally fibrous character, a molded shape, or other such configuration. The longitudinal length of second filter element 18 relative to the longitudinal length of filter element 12 can vary depending upon the application desired. The filter region (i.e., aligned filter element 12 and second filter element 18) is attached to rod 4 by tipping material 16 of the present invention which circumscribes both the filter region and an adjacent region of the rod.

[0018] In casting the plug wrap or tipping material, the water dispersible cellulose material, water soluble film forming material and optional humectant are dispersed in a liquid having an aqueous character (e.g., water) under high sheer mixing conditions to provide a mixture (i.e., a slurry). The slurry is then formed into a sheet-like shape using a conventional forming machine or other means for forming known to those skilled in the art. For example, a forming machine comprising a headbox, a continuous belt preferably formed of a non-porous material such as stainless steel, and a series of dryers can be utilized. The slurry is transferred to the headbox and is laid onto the belt as a sheet-like shape at a temperature of about 25 to 35° C. to a thickness of about 0.010 to about 0.040 inches, and preferably from about 0.015 inches to about 0.030 inches. The cast slurry is heated and dried through the series of dryers to a moisture content of about 5 to about 15 weight percent, preferably to a moisture content of about 9 to about 11 weight percent. Drying of the cast slurry can be provided using a variety of techniques. For example, the cast slurry can be (i) air dried under ambient conditions, (ii) heated on a heated metal surface, (iii) subjected to contact with heated air, or (iv) heated on a metal surface and subjected to contact with heated air.

[0019] Typically, the tobacco rod has a length which ranges from about 35 mm to about 85 mm, preferably about 40 to about 70 mm; and a circumference of about 17 mm to about 27 mm, preferably about 22.5 mm to about 25 mm. Short cigarette rods (i.e., having lengths from about 35 mm to about 50 mm) can be employed, particularly when smokable blends having a relatively high packing density are employed.

[0020] The following examples are provided in order to further illustrate various embodiments of the invention but should not be construed as limiting the scope thereof. Unless otherwise noted, all parts and percentages are by weight.

EXAMPLES 1-4

[0021] A series of plug wrap materials were made by casting the composition at a specific slit width and casting speed.

EXAMPLE 1

[0022] The slurry had the following composition: Component % Solids Basis NaCMC¹ 33.52 guar gum 22.35 glycerin 5.03 wood pulp 39.11

[0023] The slurry was cast at a slit width of 26.5 mm and a casting speed of 50 ft/min. The plug wrap material had a yellow color, a smooth texture and good strength. The plug wrap material dispersed in water in about 10 minutes.

EXAMPLE 2

[0024] Example 2 was similar to Example 1 except additional wood pulp on a percent solids on a basis was used. Component % Solids Basis NaCMC 21.51 guar gum 14.34 glycerin 5.02 wood pulp 59.14

[0025] The slurry was cast at a slit width of 26.5 mm and a casting speed of 50 ft/min. The plug wrap material had a yellow color, a smooth texture and good strength. The plug wrap material dispersed in water in about 25 minutes.

EXAMPLE 3

[0026] Example 3 is similar to Examples 1 and 2 except that additional wood pulp on a percent solid basis was added. Component % Solids Basis NaCMC 9.19 guar gum 6.13 glycerin 5.05 wood pulp 79.63

[0027] The slurry was cast at a slit width of 26.5 mm and a casting speed of 50 ft/min. The plug wrap material had a yellow color, a smooth texture and good strength. The plug wrap material dispersed in water in about 75 minutes with no stirring and about 8 minutes with slight stirring.

EXAMPLE 4

[0028] Example 4 is similar to the other examples except a higher casting speed was used. Component % Solids Basis NaCMC 27.15 guar gum 18.10 glycerin 4.98 wood pulp 49.77

[0029] The slurry was cast at a slit width of 26.5 mm and a casting speed of 60 ft/min. The plug wrap material had a yellow color, a smooth texture and good strength. The plug wrap material dispersed in water in about 25 minutes.

[0030] Examples 1-4 were then analyzed for standard properties of conventional plug wrap material, the results of which are shown on Table 1. TABLE 1 Property Example 1 2 3 4 Moisture (%) 11.29 10.38 8.97 8.19 Thickness (mm) 0.038 0.036 0.035 0.036 Basis Wt (g/m²) 29.57 28.69 28.70 29.01 Coresta 28 27 28 29 Tensile (Machine Direction) 7.9 9.0 8.6 X Tensile (Cross Direction) 6.6 6.0 8.9 X

EXAMPLES 5-8

[0031] The plug wrap material compositions for Examples 5-8 was essentially the same except wood pulp having different Canadian Standard freeness values were used. The general composition was: Component % Solids Basis NaCMC 30.00 guar gum 20.00 glycerin 5.00 wood pulp 45.00

EXAMPLE 5

[0032] The plug wrap material had a Canadian Standard freeness of −30 CSF. The sheet weight was 28 gsm, the sheet had an off-white color, and dispersed in water in about 25 minutes.

EXAMPLE 6

[0033] The plug wrap material had a Canadian Standard freeness of −220 CSF. The sheet weight was 28 gsm, the sheet had an off-white color, and dispersed in water in about 25 minutes.

EXAMPLE 7

[0034] The plug wrap material had a Canadian Standard freeness of −430 CSF. The sheet weight was 28 gsm, the sheet had an off-white color, and dispersed in water in about 30 minutes.

EXAMPLE 8

[0035] The plug wrap material had a Canadian Standard freeness of 650 CSF. The sheet weight was 28 gsm, the sheet had an off-white color, and dispersed in water in about 33 minutes.

[0036] Examples 5-8 were than analyzed for standard properties of conventional plug wrap material, the results of which are shown in Table 2. TABLE 2 Conventional Property Example 5 6 7 8 Plug Wrap Thickness (mm) 0.044 0.043 0.047 0.045 0.042 Basis Wt (g/m²) 31.05 31.63 31.26 30.95 22.81 Tensile (Machine 12.6 14.2 13.0 11.4 14.8 Direction) Tensile (Cross Direction) 3.8 4.4 5.2 5.0 3.3 Opacity 18.93 15.07 21.37 11.77 42.13

[0037] The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. The invention is defined by the following claims, with equivalents of the claims to be included therein. 

That which is claimed:
 1. An improved circumscribing plug wrap for a filter element of a smoking article, the plug wrap comprising a cast sheet of 20 to 70 percent by weight water dispersible cellulose material, 20 to 70 percent by weight of a water soluble film forming material and 0 to 10 percent by weight of a humectant.
 2. The improved plug wrap of claim 1, wherein the plug wrap further comprises a coloring agent.
 3. The improved plug wrap of claim 2, wherein the coloring agent is finely ground tobacco.
 4. The improved plug wrap of claim 1, wherein the water soluble film forming agent is a water soluble cellulosic material selected from the group consisting of carboxylmethyl cellulose and salts and derivatives thereof, methyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, ethyl hydroxyethyl cellulose, hydroxylethyl cellulose and blends thereof.
 5. The improved plug wrap of claim 1, wherein the film forming agent is a water soluble polysaccharide gum selected from the group consisting of guar gum, xanthan gum, locust bean gum, gum arabic, sodium alginate, carrageenan gum and tamarind gum and blends thereof.
 6. The improved plug wrap of claim 1, wherein the film forming agent is a combination of a water soluble cellulose material selected from the group consisting of carboxylmethyl cellulose and salts and derivatives thereof, methyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, ethyl hydroxyethyl cellulose, hydroxylethyl cellulose and blends thereof and a water soluble polysaccharide gum selected from the group consisting of guar gum, xanthan gum, locust bean gum, gum arabic, sodium alginate, carrageenan gum and tamarind gum and blends thereof.
 7. The improved plug wrap of claim 1, wherein the humectant is selected from the group consisting of polyhydric alcohols, aliphatic esters of mono-, di- or polycarboxylic acid and combinations thereof.
 8. The improved plug wrap of claim 1 further comprising 30 to 50 percent by weight calcium carbonate.
 9. The improved plug wrap of claim 1, wherein the water dispersible cellulose is wood pulp.
 10. The improved plug wrap of claim 9, wherein the cellulose is refined to a Canadian Standard freeness of between −30 and −650 CSF units.
 11. An improved cigarette tipping paper comprising a cast sheet of 20 to 70 percent by weight water dispersible cellulose material, 20 to 70 percent by weight of a water soluble film forming material and 0 to 10 percent by weight of a humectant wherein the cast sheet is printed with an ink pattern.
 12. The improved cigarette tipping paper of claim 11 further comprising a coloring agent.
 13. The improved cigarette tipping paper of claim 12, wherein the coloring agent is finely ground tobacco.
 14. The improved cigarette tipping paper of claim 11 further comprising a top coating of a lip release agent.
 15. The improved cigarette tipping paper of claim 14, wherein the lip release agent is ethyl cellulose.
 16. The improved cigarette tipping paper of claim 11, wherein the water soluble film forming agent is a water soluble cellulosic material selected from the group consisting of carboxylmethyl cellulose and salts and derivatives thereof, methyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, ethyl hydroxyethyl cellulose, hydroxylethyl cellulose and blends thereof.
 17. The improved cigarette tipping paper of claim 11, wherein the film forming agent is a water soluble polysaccharide gum selected from the group consisting of guar gum, xanthan gum, locust bean gum, gum arabic, sodium alginate carrageenan gum and tamarind gum and blends thereof.
 18. The improved plug wrap of claim 11, wherein the film forming agent is a combination of a water soluble cellulose material selected from the group consisting of carboxylmethyl cellulose and salts and derivatives thereof, methyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, ethyl hydroxyethyl cellulose, hydroxylethyl cellulose and blends thereof and a water soluble polysaccharide gum selected from the group consisting of guar gum, xanthan gum, locust bean gum, gum arabic, sodium alginate, carrageenan gum and tamarind gum and blends thereof.
 19. The improved cigarette tipping paper of claim 11, wherein the humectant is selected from the group consisting of polyhydric alcohols, aliphatic esters of mono-, di- or polycarboxylic acid and combinations thereof.
 20. The improved cigarette tipping paper of claim 11 further comprising 30 to 50 percent by weight calcium carbonate.
 21. The improved cigarette tipping paper of claim 11, wherein the water dispersible cellulose is wood pulp.
 22. The improved cigarette tipping paper of claim 21, wherein the cellulose is refined to a Canadian Standard freeness of between −30 and −650 CSF units.
 23. A cigarette having a charge of smokable material including tobacco cut filler wrapped in a circumscribing wrapping material to form a smokable rod and filter plug positioned adjacent to one end of the smokable rod, the filter plug comprising a filter element and a circumscribing filter plug wrap comprising a cast sheet wrap comprising a cast sheet of 20 to 70 percent by weight water dispersible cellulose material, 20 to 70 percent by weight of a water soluble film forming material and 0 to 10 percent by weight of a humectant.
 24. The cigarette of claim 23 wherein the filter plug is attached to the smokable rod with circumscribing tipping material comprising a cast sheet wrap comprising a cast sheet of 20 to 70 percent by weight water dispersible cellulose material, 20 to 70 percent by weight of a water soluble film forming material and 0 to 10 percent by weight of a humectant.
 25. The cigarette of claim 23, wherein the plug wrap or tipping material or both further comprises a coloring agent.
 26. The cigarette of claim 25, wherein the coloring agent is finely ground tobacco.
 27. The cigarette of claim 24, wherein the tipping material further comprises a top coating of a lip release agent.
 28. The cigarette of claim 27, wherein the lip release agent is ethyl cellulose.
 29. The cigarette of claim 23, wherein the water soluble film forming agent is a water soluble cellulosic material selected from the group consisting of carboxylmethyl cellulose and salts and derivatives thereof, methyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, ethyl hydroxyethyl cellulose, hydroxylethyl cellulose and blends thereof.
 30. The cigarette of claim 23, wherein the film forming agent is a water soluble polysaccharide gum selected from the group consisting of guar gum, xanthan gum, locust bean gum, gum arabic, sodium alginate, carrageenan gum and tamarind gum and blends thereof.
 31. The improved plug wrap of claim 23, wherein the film forming agent is a combination of a water soluble cellulose material selected from the group consisting of carboxylmethyl cellulose and salts and derivatives thereof, methyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, ethyl hydroxyethyl cellulose, hydroxylethyl cellulose and blends thereof and a water soluble polysaccharide gum selected from the group consisting of guar gum, xanthan gum, locust bean gum, gum arabic, sodium alginate, carrageenan gum and tamarind gum and blends thereof.
 32. The cigarette of claim 23, wherein the humectant is selected from the group consisting of polyhydric alcohols, aliphatic esters of mono-, di- or polycarboxylic acid and combinations thereof.
 33. The cigarette of claim 24, wherein the tipping material further comprises 30 to 50 percent by weight calcium carbonate.
 34. The cigarette of claim 23, wherein the water dispersible cellulose is wood pulp.
 35. The cigarette of claim 34, wherein the cellulose is refined to a Canadian Standard freeness of between −30 and −650 CSF units. 